Modified characteristic relaying apparatus



A ril 30, 1946. H. J. C ARUN 2,399,322

MODIFIED-CHARACTERISTIC RELAYING APPARATUS Filed Jan. 12, 1944 Equipment A 1A Protected WITNESSES: INVENTOR Herbert J. Car! in.

ATTORNEY Patented Apr. 30,

UNITED (STATE PATEENT? orncs MODIFIED CHABACTEBISTIC BELAYING APPARATUS I 200mm. (Cl.175-.-2ii4) My invention relates to relaying apparatus,

and particularly toa general means'for obtaining a modified relaying characteristic or re- I sponse, by means of electric-circuit connections,

rather than by the design of the relay-element itself.

An object of my invention is to provide an amplifier-tube means for providing two or more specially controlled single-phase quantities which may be utilized in the control or energization of any type of relaying-means, which is designed a to comparatively respond to two or more alterhating-current quantities. In a differential-rm lay combination, for example, the two line-current transformers may be utilized to energize the control-circuits of two amplifier-tubes, the outputs of which may be utilized to perform any desired relaying operation. By simple adjustment of the tube-circuits, or the tube-loading, or the tube-biasing, or by the substitution of the proper kind of tube in the'circuit, any desired tube-characteristic may be obtained, varying between a straight-line or linear response, and a substantially saturated response, in which the output of the tube is substantially constant regardless of variations in the input. The tubeoutputs are preferably associated with line-frequency segregating-means for segregating the line-frequency components from the direct-current and harmonic components.

A further object of my invention is to provide any sort of non-linear means which is interposed between each of a plurality of sources of alternating-current control-circuit relaying quantities, and the relaying-means which responds to said plurality of quantities, the previously mentioned line-frequency segregating-means being interposed to preserve an approximately sinusoidal wave-form, notwithstanding the wave-distorting efiects of the non-linear means.

A further object of my invention is to provide a controlled-circuit means for electrically produclng'a single relay-controlling single-phase, electrical quantity, which embodies within itself all of the discrimination which is desired, in order to obtain any kind of simple or complex currentcomparing or current-combining function, as in a linearly responsive difierential relay, a relay I described and claimed, and lllustrated in the accompanying drawing, the singleflgure of which is a diagrammatic view 0! circuits and apparatus illustrating my invention as applied to the diner: ential protection of an electrical equipment.

, In the drawing, I have indicated an alternatlug-current equipment to be protected, at the same having an input line-conductor 4 and an output line-conductor I. One 'or both of these line-conductors may be connected through a circuit-breaker 6, which is illustrated as having an auxiliary contact to and a trip-coil TC.

The drawing illustrates a difierential protective relaying system which is energized from two line-current transformers I and 8 which are conneeded on the two sides of the protected equipment 3.

According to my invention, I provide a separate network for responding to the output of each of the current-transformers 1 and 8, or other sources of control-circuit single-phase electrical quantities. As illustrated, each of the currenttransformers I and 8 energizes an amplifier-tube Hi, the two amplifier-tubes being identical, so that a description of one will sufllce for both. I contemplate that any known or desired form of amplifier-tube Ill be utilized, the particular tube which is illustrated being a pentode, although other forms of amplifier-tubes may be utilized. The essential feature of the tube is that it shall have a grid-circuit or other control-circuit H, a cathode-circuit l2 and a plate-circuit l3, so that the grid-circuit It will be the inputcircuit of the tube, and the cathode-plate circuit i2--l3 will be' the output-circuit of the tube. Energy for the output-circuit of the tube is supplied by means of any suitable direct-current source which is indicated by the B-battery terminals 3+ and 3-.

In accordance with my invention, the outputcircuit "-13 of each of the amplifier-tubes It) comprises a loading-resistance I4 and a tuned, parallel-resonant circuit which comprises the primary winding I! of an iron-core transformer It, the primary winding II being shunted by means of a capacitor I1 which is tuned to the primary-winding inductance so as to be resohaving a constant-percentage diflerential-characteristic, a relay having a variable-percentage diiferential-characteristic, or other types of relays.

With the foregoing and other objects in view, my invention consists in the apparatus, circuits,

nant at the; line-frequency of the protected equipment l although, in an alternative construction, the tuned circuit could conceivably be tuned to some harmonic. By utilizing a tuned circuit lB-l'l having a sufi'lciently high Q, and

- by utilizing a sufiiciently large loading-resistance it, it is possible to utilize the tuned circuit lB-i 1 systems, combinations, and methods hereinafter to selectively segregate the line-frequency component, or the selected'harmonic thereof, as dis tinguished from the direct-current component and the remaining harmonic components of the current flowing in the output-circuit I2l3 of each of the amplifier-tubes l0. By properly choosing amplifier-tubes I ll having the desired tube-characteristics, and by properly choosing the magnitude of the tube-loading resistance I, the B-battery voltage, and the voltage of the biasing or C-battery l8, any desired type of tubecharacteristic may be obtained.

The line-frequency transformers ii are shown as being provided with secondary windings l9 which are utilized, in accordance with my invention, to provide the energy for actuating or controlling any desired relaying-apparatus, in lieu of directly utilizing the energy which is supplied by the two line-current transformers 1 and 8. This output-energy of the transformer-sedondaries l9 may be utilized, either directly, or through the intermediary of any desired amplifier-means which is not shown except that I have shown a system in which the output-energy is utilized to energize a relaying-tube 20, which itself serves as an energy-amplifying means.

The outputs of the two transformer-secondaries l9 are combined so that they augment each other for an internal fault in the protected equipment, and oppose for an external fault. These two transformer-outputs are applied, through a rectifier-bridge 2|, to a unidirectional-current circuit including a resistor 22. It is generally preferable to smooth out the ripples from the unidirectional-current circuit, as by means of a shunting capacitor 23, which is intended to be representative of any ripple-suppressing means. The voltage which appears across the resistor 22 is applied to the control-grid 24 of the relaytube 20, which thus serves as a relay-means. Although I am not limited to the particular choice of relay-tube 20, I have chosen to illustrate a thyratron, or a gas-filled tube which will fire when the direct-current grid-voltage is equal to, or more positive than, a predetermined value which can be changed by altering the constants of the tube-circuits. I have also chosen to illustrate a relay-tube 20 of the double-grid type. so

that it may be operated to have a constant gridfiring voltage, relatively independently of circuitvariations.

The plate-cathode circuit of the relay-tube 20 is utilized to energize the trip-coil TC of the breaker 6, through the auxiliary breaker-switch 6a.

The use of a tube-type tripping-relay 20 means that my relaying system is inherently of a high speed. However, simple variations are possible, to introduce time-delays in a known manner, if required.

In the operation of the new differential relaying-apparatus which is shown in the drawing, the

presence of the amplifier-tubes l0 makes it possible to perform the various types of responsemodifications electrically, by way of modified electric currents and voltages, which may be elec-' trically combined, and applied to a simple overcurrent or overvoltage' relaying-means, in the form of asingle, compositely responsive, singlephase line-frequency current which is the current resulting from the combined outputs of the two transformer-secondaries L.

If the amplifier-tubes ID are so chos n, and'so loaded by the resistors N, that their dynamic operating characteristic is a straight line over the operating range, so that their outputs are respectively responsive linearly to their inputs, the differential-relay response will be such as to require a constant difference between the input and output line-currents, in order to trip the circuitbreaker 6. If the amplifier-tubes I0 and their associated circuits are so operated that the output remains relatively constant with respect to variations in input, 1. e., the dynamic operating characteristic of the amplifier is saturated, which is perhaps the most important adjustment according to my invention, the differential-relay characteristic will have a variable-percentage characteristic, which means that its sensitivity will be reduced at higher values of current, so as to prevent false operations due to poorly matched saturation-characteristics of the two current-transformers 1 and 8. It will be noted that this variable-percentage characteristic is obtained in a simple overcurrent or overvoltage-responslve relay-member 20, which avoids the use of complicated mechanical relays having restraint-elements or restraining torques. Other relay-characteristics may be obtained by intermediate adjustments of the operating-characteristics of the amplifier-tubes l0 and their associated circuits.

In polyphase equipments, if my invention is utilized in a differential relay, the drawing may be regarded as a single-line diagram, representing one phase of the equipment, or representing, in the relay-current sources 1 and 8, any phasesequence or other networks or means for deriving single-phase input and output currents for comparison by my device.

While I have illustratedmy invention in an illustrative form of embodiment, which is at present preferred, I wish it to be understood that this form of embodiment is merelyillustrative, and that my invention is susceptible of considerable variation in details of execution, without departing from the essential principles of the invention, I desire, therefore, that the appended claims shall be accorded the broadest construction 'consistent with their language and the prior art.

I claim as my invention:

1. Altemating-current relaying apparatus comprising a plurality of sources of alternating-current control-circuit relaying quantities of the same line-frequency but subject to variation in magnitude or phase relationships, amplifier-tube means associated with each of said sources for responding to said control-circuit relaying quan titles and for producing respective output-quantitles, means for substantially segregating an alternating-current component from the direct-current component of each of the output-quantities, means for combining all of said alternating-current components and for producing a single, compositely responsive, single-phase quantity, and relaying-means responsive to said last-mentioned quantity.

2. Alternating-current relaying apparatus com prising a plurality of sources of alternating-current control-circuit relaying quantities of the same line-frequency but subject to variation in magnitude or phase relationships, non-linear means associated with each of said sources for responding to said control-circuit relaying quantities and for producing respective output-quantities of controlled characteristics, including fundamental and harmonic components of different frequencies, means for substantially segregating a component of one particular frequency from the other components of each of the output-quantitles, means for combining all of said selectedfrequency components and for producing a single.

compositely responsive. single-phase quantity. and relaying-means responsive to said last-mentioned quantity.

3. The combination, with a relaying-means for responding to two controlling alternating-current quantities of the same line-frequency but subject to variation in-mag'nitude or phase relationships, of two supply-circuits for supplying two such quantities for con means, and an amplifier-tube meansand irequency-responsive segregating-means interposed between each supply-circuit and the corresponding control-circuit terminals said relayingmeans for supplying substantially sinusoidal controlling quantities to said relaying-means.

4. The combination. w th a relaying-means for responding to two controlling alternating-current quantities or the same line-frequency but subject to variation in magnitude or phase relationships, or two supply-circuits for supply n two such quantities for controlling said relayingmeans, and a non-linear means and frequencyresponsive segregating-means interposed between each supply-circuit and the corresponding control-circuit terminals of said relaying-means for,

supplying substantially sinusoidal controlling quantities or modified characteristics to said relaying-means.

5. Alternating-current relaying apparatus comprising a plurality oi sources of alternating-current control-circuit relaying quantities oi!v the same line-frequency but sublect'tc variation in magnitude or phase relationships, amplifier-tube means associated with each of said sources for responding to said control-circuit relaying quantitles and for producing respective output-quantitles, means for substantially segregating the component 0! one particular frequency from each of the output-quantities, and means for diflerentially comparing said segregated components.

8. Alternating-current relaying app ratus comprising a plurality of sources of alternating-current control-circuit relaying quantities of the same line-frequency but subject to variation in magnitude or phase relationships, non-linear means associated with each of said sources for responding to said control-circuit relaying quantitles and for producing respective output-quantitles or controlled characteristics, means for substantially segregating the component of one particular frequency from each of the output-quantities, and means for differentially comparing said segregated components.

'7. Diflerential relaying apparatus for comparing the input and output currents of an alternating-current equipment to be protected, comprising, in combination with means for deriving said input and output currents, two amplifier-tube means for responding selectively to said input and output currents and for producing respective output-quantities, means for substantially segregating the component of one particular frequency from each of the output-quantities, and'means for diiterentially comparing said lin'eefrequency components.

8. Differential relaying apparatus for comparing the input and output currents oian alternating-current equipment to be protected, comprising, in combination with means for deriving said input and output currents, two non-linear means for responding selectively to said input and output currents and for producing respective outputquantities of modified characteristics, means for substantially segregating the component of one particular irequency'irom each or the outputsaid relayin quantities, and means tor diflerentially comparing said line-frequency components.

9. Dlilerential relaying apparatus for comparin: the input and output currents of an alternatlug-current equipment to be protected. c mp ising, in combination with means for deriving said input and output currents, two amplifier-tube means for responding selectively to said input and output currents and for producing respective output-quantities, means rorsubstantially segregate ing the component oi one particular frequency from each of the output-quantities, means for combining said line-irequency components and for producing a single, compositely responsive, single-phase quantity, and relaying-means responsive to said last-mentioned quantity.

l0. Diflerential relaying apparatus for comparing the input and output currents of an alternating-current equipment to be protected, comprising, in combination with means for deriving said input and output currents, two non-linear means ior responding selectively to said input and output currents and for producing respective out-'- put-quantities o! modified characteristics, means for substantially segregating the component of one particular frequency from each of the output-quantities, means for combining said line- !requency components and ior producing a single, compositely responsive, single-phase quantity, and relaying-means responsive to said lastmentioned quantity.

11. Alternating-current relaying apparatus comprising a plurality of sources of alternatingcurrent control-circuit relaying quantities or the same line-frequency but subject to variation in magnitude or phase relationships, amplifiertu'be means associated with each 01' said sources for responding to said control-circuit relaying quantities and for producing respective outputquantities, means for substantially segregating the line-frequency component from the directcurrent component of each of the output-quantitles, means for combining all or said line-irequency components and for producing 'a single, compositely responsive, single-phase quantity, and relaying-means responsive to said last-mentioned quantity.

12. Alternating-current relaying apparatus comprising a plurality of sources of altematingcurrent control-circuit relaying quantities of the same line-frequency but subject to variation in magnitude or phase relationships, non-linear means associated with each or said sources for responding to said control-circuit relaying quanphase quantity, and relaying-means responsive to said last-mentioned quantity.

13. The combination, with a relaying-means for responding to two controlling alternating-v current quantities of the same line-frequency but subject to variation in magnitude or phase relationships, of two supply-circuits for supplying two such quantities for controlling said relaying-means, and an amplifier-tube means and line-frequency segregating-means interposed between each supply-circuit and the corresponding control-circuit terminals of said relaying-means for supplying substantially sinusoidal controlling quantities to said relaying-means.

-14. 'Ihdcombination, with a relaying-means for responding to two controlling alternatingcurrent quantities of the same line-frequency comprising a plurality of sources of alternatingcurrent control-circuit relaying quantities of the same line-frequency but subject to variation in magnitude or phase relationships, amplifier-tube means associated with each of said sources for responding to said control-circuit relaying quantities and for producing respective outputquantities, means for substantially segregating the line-frequency component from each oi the output-quantities, and means for differentially comparing said line-frequency components.

16. Alternating-current relaying apparatus comprising a plurality of sources of alternatingcurrent control-circuit relaying quantities of the same line-frequency but subject to variation in magnitude or phase relationships, non-linear means associated with each of said sources for responding to said control-circuit relaying quantities and for producing respective outputquantities of controlled characteristics, means for substantially segregating the line-frequency component from each of the output-quantities, and means for differentially comparing said line- I frequency components.

17. Differential relaying apparatus for comparing the input and output currents of an altermating-current equipment to be protected, comprising, in combination with means for deriving said input and output currents, two amplifiertube means for responding selectively to said input and output currents and for producing respective output-quantities, means for substantially segregating the line-frequency component from the direct-current and harmonic components of each of the output-quantities, and means for diflerentially comparing said line-irequency components.

18. Diflerential relaying apparatus for comparing the input and output currents 01' an alternating-current equipment to be protected, comprising, in combination with means for deriving said input and output currents, two nonlinear means for responding selectively to said input and output currents and for producing respective output-quantities of modified characteristics, means for substantially segregating the line-frequency component from each of the output-quantities, and means for differentially comparing said line-frequency components.

19. Diflerential relaying apparatus for comparing the input and output currents of an alternating-current equipment to be protected, comprising, in combination with means for deriving said input and output currents, two amplifier-tube means for responding selectively to said input and output currents and for producing respective output-quantities, means for substantially segregating the line-frequency component from each of the output-quantities, means for combining said line-frequency components and for producing a single, compositely responsive, single-phase quantity, and relayingmeans responsive to said last-mentioned quantity.

20. Differential relaying apparatus for comparing the input and output currents of an alternating-current equipment to be protected, comprising, in combination with means for deriving said input and output currents, two non-linear means for responding selectively to said input and output currents and for producing respective output-quantities of modified characteristics, means for substantially segregating the line-irequency component from each of the outputquantities, means for combining said line-irequency components and for producing a single, compositely responsive, single-phase quantity, and relaying-means responsive to said last-mentioned quantity.

HERBERT J. CARLIN. 

